Check Credit Card Validity using Luhn Algorithm

Question

I tried to check the validation of credit card using Luhn algorithm, which works as the following steps:

1. Double every second digit from right to left. If do

Answer 1

I'll use 5 digit card numbers for simplicity. Let's say your card number is 12345; if I read the code correctly, you store in array the individual digits:

array[] = {1, 2, 3, 4, 5}

Since you already have the digits, in sumOfOddPlace you should do something like

public static int sumOfOddPlace(long[] array) {
    int result = 0;
    for (int i = 1; i < array.length; i += 2) {
        result += array[i];
    }
    return result;
}

And in sumOfDoubleEvenPlace:

public static int sumOfDoubleEvenPlace(long[] array) {
    int result = 0;
    for (int i = 0; i < array.length; i += 2) {
        result += getDigit(2 * array[i]);
    }
    return result;
}